2.0T E85 Fuel Tuning Basics

[mopedwizard]

I'm working my way up to E85 and I'm watching my LTFT compensate. I'm at E40ish at the moment and LTFT are adding 16-23% across the board. Logically this all makes sense to me due to ethanol requiring more fluid volume. What I do next is where I need help.

Adjusting fuel volume:
What is the "best" way to deliver 20-30% more fuel and get my LTFT closer to zero? I don't have a flex fuel option (that I'm aware of), so I plan to reflash when my ethanol content changes above a certain threshold. I've read that I should adjust lambda and leave stoich alone. I've also read that I should adjust shoich and leave lambda alone. I've also read various other ways to do this that all sound like bandaids. Here's a screenshot for refence

Attachment 137355

Watching injector Duty Cycle
Now that I'm working the fuel system so hard, I want to watch my duty cycle. I found pulse width, but I haven't found a way to read injector duty cycle. Do I need to calculate duty cycle from pulse width and rpm or is there a built in way to monitor injector duty cycle?

2.0 2017 Fusion AWD

[Evo8john]

It's unlikely you will have enough injector/fuel pump to go to full E85.

You should be able to use the flex logic from one of the other Ford flex vehicles of the same year to populate those tables though, if you want to dabble with it. Just monitor your HPFP expected vs actual pressures to see if it's able to keep up.

As far as the injector duty cycle, you could probably set up a formula based on injector opening time vs available opening time.

[mopedwizard]

Thanks for the help

I ended up finding a post from a HP tech that said changing stoich was best so I gave that a shot.

Stoich is now 10.7 and I took it for a spin without a KAM reset. LTFT and STFT were pretty much cancelling each other out, so I reset KAM and I?m not seeing any trim over 10%.

I also found an injector duty cycle parameter in VCM Scanner, but it?s saying I?m never getting over 30% and that?s not making sense to me. I figured I would me pushing the limits of fueling on stock injectors so this can?t be a good number.

I?ll log those pressures like Evo8john suggested and see what I find.

I?m trying to wrap my head around how to calculate injector duty cycle available time for a direct injection setup. It has to be less than port injection right? I?m thinking it will be a formula of pulse width and rpm but I?m not sure of a 720 degree firing cycle how many degrees I can actually afford to have the injectors open.

[Seishuku]

Injector duty on direct injection is different than port injection, the duty you see is correct... but because there's a limited window of cam/crank degrees that it can actually spray fuel at, you can never really max out the injector.

[mopedwizard]

I logged rail pressure desired vs actual and it seems pretty good just scrolling through the values. I?m reading up on math parameters in the scanner so I can graph out the difference and look for max values.

It looks to me like there are conditions where the rail pressure is low and the pulse width is huge (7.8ms at max) and there are also times where the pulse width is a lot more reasonable and the rail pressure is high (2900psi).

I plan to also math out an appropriate time for the injector to fire vs injector pulse width to see how close to the limit I am.

This brings up my next question:
In a DI application, can the injectors fire in the compression stroke or only in the intake stroke? Are there any rules about intake valves being open while firing the injector for atomization etc?

The first iteration of my injector graph will probably be super simple. I?m thinking of intake stroke duration vs pulse width. I?m going to guess pulse width is greater than intake stroke duration at the moment at high rpm and that?s why the rail pressure goes to the moon trying to catch up.

[Seishuku]

You can push the window by increasing "max injection angle", you can go as high as 290 degrees on that without causing issues, that's where I have mine set for my Mustang and seems to help and I've had 400+ ftlbs torque on E30 without running into fueling issues (low rail pressure or going lean).

You're definitely not going to be able to run full E85 on stock fuel system though, the HPFP will not keep up, not enough flow.

If you need larger injectors, you *can* use 2.3 Mustang/Focus RS injectors, they are slightly larger (30%?), and the 2.0 has the same HPFP as the 2.3's... But the pump still will run out of flow.

[mopedwizard]

Sorry guys, I didn't really make it clear that I'm on E85 since a few posts ago. No boom yet! about 50-60 miles in since fill up.

My local pump claims 70% content on E85 but I haven't actually measured the content. There was a little (couple gallons) E40ish mix left in the tank when I put 10 gallons of E85. I figure I'm at at least 60% at this point.

I know this is risky given lots of advice that I shouldn't do this, but I'm taking it easy on WOT pulls - only 5 or 6 0-60 MPH pull so far.

[Stevekreger]

Sorry guys, I didn't really make it clear that I'm on E85 since a few posts ago. No boom yet! about 50-60 miles in since fill up.

My local pump claims 70% content on E85 but I haven't actually measured the content. There was a little (couple gallons) E40ish mix left in the tank when I put 10 gallons of E85. I figure I'm at at least 60% at this point.

I know this is risky given lots of advice that I shouldn't do this, but I'm taking it easy on WOT pulls - only 5 or 6 0-60 MPH pull so far.

when you do a run log lambda, that will let you know if your fuel system is keeping up. i don't know what your enrichment is set at, but if you can hold .80 to .85 throughout the entire run your good. You can go pretty lean on e85, but i would try to get maybe .84-.85 start with short runs first

[mopedwizard]

I haven?t played with lambda yet, but I?m loving the change so far. I feel like power delivery is so much more linear across pedal position where as before there was a big dead spot from 50% to 90% throttle.

I had my first trouble with cold cranking in 30 degree weather. I increased cold cranking fuel by 30% and moved the spark to TDC (0 deg) based on some reading from other tuners. It still takes a half a second longer to fire than it did with gas, but it hasn?t let me down since those adjustments. I think I?m going to leave fuel and spark alone for now and attack the other reason for diving into tuning - fixing a rough 2-3 shift.

[mopedwizard]

Update:

I made almost 21 lbs of boost at 4000-4500 rpm on E85 (70%) and it's still one piece. I'm reading 35.4 peak on MAP and I'm adjusting 14.5 for my elevation. Does that math hold up? The fuel pressure went to almost 3k psi. I let it make a lot of boost until high rpm where I pull back.

The lowest reading on WB EQ Ratio was .73 when it was commanding .807. That's at full chooch and high rpm. I plan to keep the boost up at low rpm, but have it fall off at high rpm to keep the fuel system from running out of duty cycle. I've started moving all the shift schedules to keep WOT shifts to 5k RPM.

I'm having a blast. I hope my next post isn't that I scattered parts. I think I pushed it pretty damn hard.

[Coyote Chaser]

I'm working my way up to E85 and I'm watching my LTFT compensate. I'm at E40ish at the moment and LTFT are adding 16-23% across the board. Logically this all makes sense to me due to ethanol requiring more fluid volume. What I do next is where I need help.

Adjusting fuel volume:
What is the "best" way to deliver 20-30% more fuel and get my LTFT closer to zero? I don't have a flex fuel option (that I'm aware of), so I plan to reflash when my ethanol content changes above a certain threshold. I've read that I should adjust lambda and leave stoich alone. I've also read that I should adjust shoich and leave lambda alone. I've also read various other ways to do this that all sound like bandaids. Here's a screenshot for refence

Attachment 137355

Watching injector Duty Cycle
Now that I'm working the fuel system so hard, I want to watch my duty cycle. I found pulse width, but I haven't found a way to read injector duty cycle. Do I need to calculate duty cycle from pulse width and rpm or is there a built in way to monitor injector duty cycle?

2.0 2017 Fusion AWD

Concerning Long Term Fuel Trim; Based on my understanding of information from HP Academy, you should disable your LTFT, when trying to zoom in on a pacific Ethanol content. I did something similar when I started racing with blended fuel, I would reset my ECU between rounds of racing.

[Coyote Chaser]

Thanks for the help

I ended up finding a post from a HP tech that said changing stoich was best so I gave that a shot.

Stoich is now 10.7 and I took it for a spin without a KAM reset. LTFT and STFT were pretty much cancelling each other out, so I reset KAM and I?m not seeing any trim over 10%.

I also found an injector duty cycle parameter in VCM Scanner, but it?s saying I?m never getting over 30% and that?s not making sense to me. I figured I would me pushing the limits of fueling on stock injectors so this can?t be a good number.

I?ll log those pressures like Evo8john suggested and see what I find.

I?m trying to wrap my head around how to calculate injector duty cycle available time for a direct injection setup. It has to be less than port injection right? I?m thinking it will be a formula of pulse width and rpm but I?m not sure of a 720 degree firing cycle how many degrees I can actually afford to have the injectors open.

I went the route of Port Injection with an Independant Controller at a cost of $1400.
I'm using the stock fuel system including fuel pumps. The Port Injectors tee off the fuel line before the high pressure pump and I also am using an ethanol content sensor and am viewing the data via smart phone.

PS: Last time I purchased pump ethanal, it was E66.

[Coyote Chaser]

Update:

I made almost 21 lbs of boost at 4000-4500 rpm on E85 (70%) and it's still one piece. I'm reading 35.4 peak on MAP and I'm adjusting 14.5 for my elevation. Does that math hold up? The fuel pressure went to almost 3k psi. I let it make a lot of boost until high rpm where I pull back.

The lowest reading on WB EQ Ratio was .73 when it was commanding .807. That's at full chooch and high rpm. I plan to keep the boost up at low rpm, but have it fall off at high rpm to keep the fuel system from running out of duty cycle. I've started moving all the shift schedules to keep WOT shifts to 5k RPM.

I'm having a blast. I hope my next post isn't that I scattered parts. I think I pushed it pretty damn hard.

You shouldn't have any issues with high boost at high rpm. Provided your running the stock turbocharger, your boost should trail off as rpm increases.
If your boost continues to rise, you may have an issue, usually associated with exhaust flow and/or timing.

[Coyote Chaser]

Were you able to locate a (OEM) map or tune file for a flex fuel Ford Fusion?? I have a 2014 Ecoboost Fusion and I'd like to be able to run pump ethanol (flex fuel).